For example: Agilent E4440A or Anritsu 68369
Continental Microwave Microwave Components
Continental Microwave LPTSL42-1A-A
WR42 Waveguide Termination, K Band , 18-26.5 GHz
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Manufacturer: Continental Microwave
Continental Microwave RA22-OS50-0F-24B-C
WR22 TO TYPE K (f) ADAPTER , SQUARE COVER WAVEGUIDE
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Manufacturer: Continental Microwave
Continental Microwave RA28-K-F-1A-A
WR28 - 3.5mm (F) Transit, R Band, 26.5 GHz - 40 GHz
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Manufacturer: Continental Microwave
Continental Microwave RA28-K-F-7B-C
WR28 - 3.5mm (F) Transit, R Band, 26.5 - 40 GHz
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Manufacturer: Continental Microwave